In-Plane Zeeman-Field-Induced Majorana Corner and Hinge Modes in an s -Wave Superconductor Heterostructure

Abstract

Second-order topological superconductors host Majorana corner and hinge modes in contrast to conventional edge and surface modes in two and three dimensions. However, the realization of such second-order corner modes usually demands unconventional superconducting pairing or complicated junctions/layered structures. Here we show that Majorana corner modes could be realized using a 2D quantum spin Hall insulator in proximity contact with an s-wave superconductor and subject to an in-plane Zeeman field. Beyond a critical value, the in-plane Zeeman field induces opposite effective Dirac masses between adjacent boundaries, leading to one Majorana mode at each corner. Similar paradigm also applies to 3D topological insulators with the emergence of Majorana hinge states. Avoiding complex superconductor pairing and material structure, our scheme provides an experimentally realistic platform for implementing Majorana corner and hinge states.

Boundary-Obstructed Topological High- Tc Superconductivity in Iron Pnictides

“…In superconductors, despite the absence of a Wannier description, particle-hole and/or chiral symmetries can also protect the existence of corner-localized MZMs. Recently, several proposals have been put forward for the realization of higher-order topological superconductors (HOTSC) in 2D or 3D [25,[30][31][32][33][34][35][36][37][38][39][40][41][42][43][44], some of which include certain iron-based superconductor compounds [30,31,39,43,44]. Setting aside the fact that the complete characterization of HOTSC by topological invariants is still missing, there is, in addition, a significant disconnect between the toy models studied in those works and actual material candidates.…”

Quadrupole spin polarization as signature of second-order topological superconductors

“…SOTSCs with four corner states. Next, we generalize our findings to a different class of SOTSCs and consider a SOTSC hosting a quadruplet of MCSs [39][40][41][42][43][44][45][46][47][48]. The basic ingredient of our construction here is a minimalist version of a 2D TI [3] proximity coupled to an s-wave superconductor with amplitude sc , introduced in Ref.…”

“…The basic ingredient of our construction here is a minimalist version of a 2D TI [3] proximity coupled to an s-wave superconductor with amplitude sc , introduced in Ref. [47]. The corresponding Hamiltonian reads…”

Topological and holonomic quantum computation based on second-order topological superconductors

“…We start with considering simple two-dimensional SOTSs realized, for instance, in QSHIs in the presence of superconductivity and moderate in-plane magnetic fields [44][45][46][47]. The minimal model for the SOTSs can be written as H = H 0 + H ex with…”